Movable reflective device

Abstract

An actuator includes an arm starting end having a piezoelectric element, a first end of the arm starting end connected to an inner side of a fixed frame, the arm starting end extending in a straight line, along a Y-axis direction through a gap between the fixed frame and a mirror surface, from the first end to beyond a middle point of an outer side of the mirror surface; an arm terminating end including a first end connected to the middle point of the outer side of the mirror surface, the arm terminating end extending parallel to the arm starting end; and an arm relay that connects a second end of the arm starting end to a second end of the arm terminating end, the arm relay being formed in a zigzag.

What is claimed is: 
     
       1. A movable reflective device comprising:
 a fixed frame, the fixed frame having a flat plate-like shape; 
 a rocker that includes a reflective surface, the rocker being disposed within the fixed frame such that a gap exists between the rocker and the fixed frame, a mirror surface being formed on a first side of the rocker; and 
 a first actuator that connects the fixed frame to the rocker, the first actuator being a pair of flexible members on which a first piezoelectric element, configured to be capable of expansion and contraction, is formed at a portion extending along a first direction or a portion extending along a second direction that intersects the first direction, each of the pair of members being disposed on each side in the second direction of the rocker, the first actuator being deformed by the expansion and contraction of the first piezoelectric element, thereby causing the rocker to rock with respect to the fixed frame around a first rotational axis, wherein 
 the first actuator includes: 
 a first arm starting end on which the first piezoelectric element is formed, a first end of the first arm starting end being connected to an inner side of the fixed frame, the first arm starting end extending in a straight line, along the first direction through the gap between the fixed frame and the rocker, from the first end to beyond a middle point of an outer side of the rocker, 
 a first arm terminating end including a first end connected to the middle point of the outer side of the rocker, the first arm terminating end extending parallel to the first arm starting end, and 
 a first arm relay that connects a second end of the first arm starting end to a second end of the first arm terminating end, the first arm relay being formed in a zigzag by alternately connecting a first arm connector extending along the second direction and a first arm extension extending parallel to the first arm starting end and on which the first piezoelectric element is formed, and 
 the first arm terminating end includes: 
 a first portion on which the first piezoelectric element is formed, the first portion having a thickness that is less than a thickness of the rocker such that the first portion deflects by the expansion and contraction of the first piezoelectric element to cause the rocker to rock, and 
 a second portion that has a thickness greater than the thickness of the first portion and connects the first portion to the rocker, wherein the rocker includes: 
 a movable frame comprising a flat plate-like shape, the movable frame being connected to the first actuator and disposed within the fixed frame such that a gap exists between the movable frame and the fixed frame, 
 a mirror surface having a flat plate-like shape, the mirror surface including a reflective surface and being disposed within the movable frame such that a gap exists between the mirror surface and the movable frame, and 
 a second actuator that connects the movable frame to the mirror surface, the second actuator being a pair of flexible members on which a second piezoelectric element, configured to be capable of expansion and contraction, is formed at a portion extending along the first direction or a portion extending along the second direction, each of the pair of members being disposed on each side in the first direction of the mirror surface, the second actuator being deformed by the expansion and contraction of the second piezoelectric element, thereby causing the mirror surface to rock with respect to the movable frame around a second rotational axis that intersects the first rotational axis, wherein the second arm terminating end includes: 
 a third portion on which the second piezoelectric element is formed, the third portion having a thickness that is less than a thickness of the mirror surface such that the third portion deflects by the expansion and contraction of the second piezoelectric element to cause the mirror surface to rock, and 
 a fourth portion that has a thickness greater than the thickness of the third portion and connects the third portion to the mirror surface. 
 
     
     
       2. The movable reflective device according to  claim 1 , wherein a weight is attached to the rocker. 
     
     
       3. The movable reflective device according to  claim 1 , wherein a boundary between the first portion and the second portion is provided along a direction of the first rotational axis. 
     
     
       4. The movable reflective device according to  claim 1 , wherein the thickness of the second portion is the same as the thickness of the rocker. 
     
     
       5. The movable reflective device according to  claim 1 , wherein the second actuator includes:
 a second arm starting end on which the second piezoelectric element is formed, a first end of the second arm starting end being connected to an inner side of the movable frame, the second arm starting end extending in a straight line, along the second direction through the gap between the movable frame and the mirror surface, from the first end to beyond a middle point of an outer side of the mirror surface, 
 a second arm terminating end including a first end connected to the middle point of the outer side of the mirror surface, the second arm terminating end extending parallel to the second arm starting end, and 
 a second arm relay that connects a second end of the second arm starting end to a second end of the second arm terminating end, the second arm relay being formed in a zigzag by alternately connecting a second arm connector extending along the first direction and a second arm extension extending parallel to the second arm starting end and on which the second piezoelectric element is formed. 
 
     
     
       6. The movable reflective device according to  claim 5 , wherein
 each of the first actuators is disposed with two-fold rotational symmetry about the mirror surface, 
 each of the second actuators is disposed with two-fold rotational symmetry about the mirror surface, and 
 a direction from the first end toward the second end of the first arm starting end, and a direction from the first end toward the second end of the second arm starting end are the same or opposite direction with respect to a rotational direction around the mirror surface. 
 
     
     
       7. The movable reflective device according to  claim 1 , wherein a boundary between the third portion and the fourth portion is provided along a direction of the second rotational axis. 
     
     
       8. The movable reflective device according to  claim 1 , wherein the thickness of the fourth portion is the same as the thickness of the mirror surface. 
     
     
       9. A movable reflective device, comprising:
 a fixed frame, the fixed frame having a flat plate-like shape; 
 a rocker that includes a reflective surface, the rocker being disposed within the fixed frame such that a gap exists between the rocker and the fixed frame, a mirror surface being formed on a first side of the rocker; and 
 a first actuator that connects the fixed frame to the rocker, the first actuator being a pair of flexible members on which a first piezoelectric element, configured to be capable of expansion and contraction, is formed at a portion extending along a first direction or a portion extending along a second direction that intersects the first direction, each of the pair of members being disposed on each side in the second direction of the rocker, the first actuator being deformed by the expansion and contraction of the first piezoelectric element, thereby causing the rocker to rock with respect to the fixed frame around a first rotational axis, wherein 
 the first actuator includes: 
 a first arm starting end on which the first piezoelectric element is formed, a first end of the first arm starting end being connected to an inner side of the fixed frame, the first arm starting end extending in a straight line, along the first direction through the gap between the fixed frame and the rocker, from the first end to beyond a middle point of an outer side of the rocker, 
 a first arm terminating end including a first end connected to the middle point of the outer side of the rocker, the first arm terminating end extending parallel to the first arm starting end, and 
 a first arm relay that connects a second end of the first arm starting end to a second end of the first arm terminating end, the first arm relay being formed in a zigzag by alternately connecting a first arm connector extending along the second direction and a first arm extension extending parallel to the first arm starting end and on which the first piezoelectric element is formed, 
 the rocker includes: 
 a movable frame comprising a flat plate-like shape, the movable frame being connected to the first actuator and disposed within the fixed frame such that a gap exists between the movable frame and the fixed frame, 
 a mirror surface having a flat plate-like shape, the mirror surface including a reflective surface and being disposed within the movable frame such that a gap exists between the mirror surface and the movable frame, and 
 a second actuator that connects the movable frame to the mirror surface, the second actuator being a pair of flexible members on which a second piezoelectric element, configured to be capable of expansion and contraction, is formed at a portion extending along the first direction or a portion extending along the second direction, each of the pair of members being disposed on each side in the first direction of the rocker, the second actuator being deformed by the expansion and contraction of the second piezoelectric element, thereby causing the mirror surface to rock with respect to the movable frame around a second rotational axis that intersects the first rotational axis, and 
 the movable reflective device further includes: 
 a first detection electrode, provided at a first boundary portion where the first actuator connects to the fixed frame, and provided between the first actuator and the fixed frame along a line in the first direction, that detects displacement of the first actuator, and 
 a second detection electrode, provided at a second boundary portion where the second actuator connects to the movable frame, and provided between the second actuator and the movable frame along the line in the second direction, that detects displacement of the second actuator. 
 
     
     
       10. A movable reflective device comprising:
 a fixed frame, the fixed frame having a flat plate-like shape; 
 a rocker that includes a reflective surface, the rocker being disposed within the fixed frame such that a gap exists between the rocker and the fixed frame, a mirror surface being formed on a first side of the rocker; and 
 a first actuator that connects the fixed frame to the rocker, the first actuator being a pair of flexible members on which a first piezoelectric element, configured to be capable of expansion and contraction, is formed at a portion extending along a first direction or a portion extending along a second direction that intersects the first direction, each of the pair of members being disposed on each side in the second direction of the rocker, the first actuator being deformed by the expansion and contraction of the first piezoelectric element, thereby causing the rocker to rock with respect to the fixed frame around a first rotational axis, wherein 
 the first actuator includes: 
 a first arm starting end on which the first piezoelectric element is formed, a first end of the first arm starting end being connected to an inner side of the fixed frame, the first arm starting end extending in a straight line, along the first direction through the gap between the fixed frame and the rocker, from the first end to beyond a middle point of an outer side of the rocker, 
 a first arm terminating end including a first end connected to the middle point of the outer side of the rocker, the first arm terminating end extending parallel to the first arm starting end, 
 a first arm relay that connects a second end of the first arm starting end to a second end of the first arm terminating end, the first arm relay being formed in a zigzag by alternately connecting a first arm connector extending along the second direction and a first arm extension extending parallel to the first arm starting end and on which the first piezoelectric element is formed, and 
 a first detection electrode, provided at a first boundary portion where the first actuator connects to the fixed frame, and provided between the first actuator and the fixed frame along a line in the first direction, that detects displacement of the first actuator.